Originally Posted by
Check Airman
Thanks for that. Interesting response in post #7. That could well be it. Would love to see a reference for it if anyone has one.
Yes, as described in that post, ground spoiler deployment is affected by the PFC speedbrake inhibit function. The inhibit function operates when the pitch attitude is more than 2° with the aircraft on the ground, or during the first 1.25 seconds after main landing gear air-to-ground transition. On touchdown, the auto speedbrake control commands the speedbrake lever to move rearwards to deploy the spoilers. With the inhibit function active, outboard spoilers 2, 5, 10 and 13 do not deploy, and the inboard spoilers (6, 7, 8 and 9) are limited to 20°. The mechanically controlled spoilers (4 and 11) are not affected by the inhibit function - they only deploy when the speedbrake lever moves past 54°.
Of course none of this is described in the pilot manuals. It's covered in the B777 Aircraft Maintenance Manual, 27-61-00, under "Spoiler and Speedbrake Control - Functional Description", and in the maintenance training manuals based on that document. Check with your airline.